Find the x-intercepts for the parabola defined by this equation:
y = -4x^2 - 4x + 8
Write your answer as two ordered pairs:
(x1,y1),(x2,y2)
Separate the values with a comma. Round, if necessary, to the nearest hundredth.

Question

Find the x-intercepts for the parabola defined by this equation:
y = -4x^2 - 4x + 8
Write your answer as two ordered pairs:
(x1,y1),(x2,y2)
Separate the values with a comma. Round, if necessary, to the nearest hundredth.

lucaz · Answer

factor out -4
-4(x^2+x-2), rewrite x as -x+2x
-4(x^2-x+2x-2), factor out x-1
-4[(x-1)x+(x-1)2]
-4(x-1)(x+2)=0
x-1=0 -> x=1
x+2=0 -> x=-2
the x-intercepts are (1,0) and (-2,0)

anonymous · Answer

Does it matter that it showed that the ordered pair has to be:

$$(x _{1},y_{1}),(x _{2},y_{2})$$

lucaz · Answer

(x1,y1) is a pair and (x2,y2) is the other pair..

lucaz · Answer

it could be (x0,y0) and (x1,y1), it doesn't matter

anonymous · Answer

Ok

anonymous · Answer

Thanks Lucaz :)